Preparation of pectin biopolymer electrolyte for zinc-ion battery application

In recent years, there is a demand for electrochemical devices based on biopolymer electrolyte over synthetic polymer electrolyte. In this study, development of zinc ion conducting membrane using pectin and ZnCl2 has been made by solution casting technique. Developed polymer electrolyte membrane has been characterized by X-ray diffraction analysis (XRD) to study the crystalline/amorphous nature of the polymer electrolyte. Fourier transform infrared analysis (FTIR) confirms the complex formation between polymer and salt. The glass transition temperature (Tg) of the biopolymer membrane has been studied by differential scanning calorimetry (DSC). AC impedance technique has been used to study the ionic conductivity of the samples. The pectin with ZnCl2 in the ratio of 40 M.wt% of pectin:60 M.wt% of ZnCl2 exhibits the highest ionic conductivity in the order of 4.49 × 10−3 S/cm having high amorphous nature. Linear sweep voltammetry (LSV) confirms the highest ionic conductivity biopolymer membrane has got electrochemical window to 2.36 V. Using the highest conductivity polymer electrolyte, zinc ion battery has been fabricated and output voltage is measured. The open-circuit voltage of the constructed zinc ion battery is found to be 1.84 V.